You really need to be vigilant, and trust very few, is my experience. Just a few days afetr signing up with PayPal, I received a number of e-mails asking me to confirm my account by clicking the link provided. I didn't. A buddy mentioned a similar experience and explained, PayPal has an e-mail address to which one can forward such messages. I forwarded and then received a thank you from Paypal and the confirmation, they hadn't issued the request (and never will). But for a number of months, similar requests kept pouring in. Then they stopped. I can't understand how someone (outside of PayPal) knew, I had signed up!
Some years ago I was selling two Zeiss lenses on ebay. I received a message from a member, through ebay channels who asked, "did I know what was being written about me in the ebay forum and if it were true?" I had read this message while signed into ebay. At the bottom of the page was a link to the forum. After clicking, they asked for my password again. Though I thought it odd, I wanted to get to the bottom of things, so I signed in again. The link took me nowhere and I spent a while searching for a possibility to enter the forum and find any thread concerning me.
A few days later a fellow interested in my lens asked me, how many lenses I was selling and why I had the same item(s) for sale in different auctions. What sort of scam was I running?! As I was wondering what had happened, ebay froze my account and asked me what had happened. I explained, they informed the buyers of the fictive lenses, I created a new password, my two original auctions continued and the matter was over for me. I don't know how many folks purchased the alleged lenses or how many paid. But it was a lesson I won't forget.
I'm far more careful today.